I have a question about how to achieve a talking animal for an small upcoming shoot I am planning. What would the best way to go about this be? Would this be a better practical effect achieved during production or can I achieve a realistic looking effect in post-production without too much hassle? I am looking for something similar to what was achieved in Babe, and yes I know they had a large budget and effect team working on it, but I guess I am hoping that there have been enough advancements in the last 21 years in software capabilities to make this possible. Anyway, what are your thoughts? And how would you go about it, if you had to? *I'm just trying to figure out where to even start with this as everything I've found so far online either looks unrealistic or deliberately shrouded in mystery on how to achieve this effect.

Depends on the animal. "Mr. Ed" back in the day was achieved practically with peanut butter. The "Talking Kitty Cat" channel on YouTube features a fowl-mouthed feline that is practical as well: the owner just runs around with food and his camera, getting the cat to meow, then cuts it together and writes a script after.
If you're set on doing it digitally, I think it's more work than you realize and you should probably find an effects house to help you.

I don't know your story but there are also other creative ways to do this, like, if an animal is talking but someone is hallucinating maybe their mouths don't even move. Or maybe the person hears their thoughts and no one else does and explain that in the story. Or maybe there's a special collar with a small speaker, when put on an animal, you hear their thoughts in a human voice, etc. etc.

You guys are giving me great ideas for a new short! I'm thinking of using a hand puppet, so I can mouth the words in real time. The bottom jaw of that could be masked over the shot of the real dog's mouth. I need to try this, if for any reason, the fun of it.

In the world of CGI this effect is very basically accomplished by projecting the image of the animal onto a model that matches the shape of the animal's mouth area . The animal is in the shot, typically with its mouth shut. The model is animated to make it appear to be talking. Once rendered, the animated animal mouth area is comp'ed over the footage of the animal. Presto! The animal is talking. Obviously that is a very basic explanation and thee is more to consider. For example; if the animal in the shot is moving, the cgi person has to animate the mouth model moving too... It is not hard to do but it is time consuming.